Creating "C Array" in Python-CodePudding

I am reading a book which is using ctypes to create C Array in python.

import ctypes

class Array:
    def __init__(self, size):        
        array_data_type = ctypes.py_object * size
        self.size = size
        self.memory = array_data_type()
        
        for i in range(size):
            self.memory[i] = None

I understand that self.memory = array_data_type() is creating a memory chunk which is basically a consecutive memory having ctypes.py_object * size as the total size.

How self.memory[i] is related to self.memory?

My understanding is that self.memory has no indexing and it is an object representing one single memory chunk.

CodePudding user response：

self.memory here is an array of NULL PyObject* pointers.

>>> import ctypes
>>> array_type = ctypes.py_object * 3
>>> array = array_type()
>>> array[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: PyObject is NULL

Which means self.array can contains three elements of type Pyobject(Any Python object). So this is valid.

>>> import ctypes
>>> array_type = ctypes.py_object * 3
>>> array = array_type()
>>> for i in range(3):
...     array[i] = f"{i}: test string"
...
>>> array._objects
{'0': '0: test string', '1': '1: test string', '2': '2: test string'}